Shock tube

A shock tube is an instrument used to replicate and direct blast waves at a sensor or model in order to simulate explosions and their effects, usually on a smaller scale.

[3] In the 1930s it was rediscovered by W. H. Payman and WCF Shepherd of English Safety in Mines Research Board in order to study underground methane explosions, but the term was not coined until Bleakney et al. publication of 1949.

[4][5] In the 1940s, interest revived and shock tubes were increasingly used to study the flow of fast moving gases over objects, the chemistry and physical dynamics of gas phase combustion reactions.

The modern version of the shock tube was developed during WWII at Princeton University by a group led by Walker Bleakney,[6] who published overviews of their studies in 1946 and 1949.

The driver gas is usually chosen to have a low molecular weight, (e.g., helium or hydrogen) for safety reasons, with high speed of sound, but may be slightly diluted to 'tailor' interface conditions across the shock.

The interface, across which a limited degree of mixing occurs, separates driven and driver gases is referred to as the contact surface and follows, at a lower velocity, the lead wave.

A 'Chemical Shock Tube' involves separating driver and driven gases by a pair of diaphragms designed to fail after pre-determined delays with an end 'dump tank' of greatly increased cross-section.

The fluid flow in the driven gas can be used much as a wind tunnel, allowing higher temperatures and pressures therein [18] replicating conditions in the turbine sections of jet engines.

Results from shock tube experiments can be used to develop and validate numerical model of the response of a material or object to an ambient blast wave without shrapnel or flying debris.

Shock tubes can be used to experimentally determine which materials and designs would be best suited to the job of attenuating ambient blast waves without shrapnel or flying debris.